I was getting at the old "If a tree falls..." question. It would seem to me, who has never even taken a course in astronomy or astrophysics but has followed the field through Scientific American, etc., that a general direction of spin was established early in the evolution of our galaxy and, probably, most solar systems share that spin orientation. It appears that our present galaxy has absorbed numerous other galaxies over time and I would not be surprised if they all had a similar spin, all appearing to come from the same big bang and all. So a counter rotating exo-solar planet would be a very long shot. But a hit by something with the same or greater mass, even with the same spin, which is traveling with comperable velocity as our planet through the solar system, possibly significantly out of the ecliptic, could disperse enough of the Earth's mass into other orbits that there might not be a planet in the earth's position post impact. Naturally, there would be no humans.  

As the Dutch said while fighting the Spanish: "It is not necessary to have hope in order to persevere."